Commit Graph

16 Commits

Author SHA1 Message Date
Fangrui Song d4306e90cb [ELF][X86] Allow PT_LOAD to have overlapping p_offset ranges on EM_X86_64
Port the D64906 technique to EM_X86_64.

Differential Revision: https://reviews.llvm.org/D67482

llvm-svn: 371958
2019-09-16 07:05:34 +00:00
Fangrui Song b159906a9a [test] Change llvm-readobj -long-option to --long-option or well-known short options. NFC
Also change some options that have different semantics (cause confusion) in llvm-readelf mode:

-s => -S
-t => --symbols
-sd => --section-data

llvm-svn: 359651
2019-05-01 05:49:01 +00:00
Fangrui Song 95851515d7 Add a CIE with length 0 unconditionally.
Summary: This is not technically required, but glibc unwind-dw2-fde.c classify_object_over_fdes expects there is a CIE record length 0 as a terminator.

Reviewers: ruiu, espindola

Subscribers: emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D46566

llvm-svn: 331708
2018-05-08 01:19:16 +00:00
George Rimar d46753e421 [ELF] - Do --hash-style=both by default.
Its PR34712,

GNU linkers recently changed default values to "both" of "sysv".
Patch do the same for all targets except MIPS, where .gnu.hash
section is not yet supported.

Code suggested by Rui Ueyama.

Differential revision: https://reviews.llvm.org/D38407

llvm-svn: 315051
2017-10-06 09:37:44 +00:00
Rafael Espindola b691ccf0a5 Revert "Add terminator to .eh_frame sections"
This reverts commit r296378.

I am pretty sure this is incorrect. In particular, for just

        .cfi_startproc
        nop
        .cfi_endproc

We now add an extra 4 zeros that neither bfd nor gold add.

llvm-svn: 296503
2017-02-28 18:55:08 +00:00
Rui Ueyama 1720ef1343 Add terminator to .eh_frame sections
Patch by Mark Kettenis.

Currenlty ld.lld does not add a terminator (a CIE with its length field
set to zero) to the .eh_frame sections it generates.  While the relevant
standards (the AMD64 SysV ABI and the Linux LSB) are not explicit about
this, such a terminator is expected by some unwinder implementations and
seems to be always emitted by ld.bfd. In addition to that, the Linux LSB

  https://refspecs.linuxfoundation.org/LSB_5.0.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html#EHFRAME

explicitly says that

  The .eh_frame section shall contain 1 or more Call Frame Information
  (CFI) records.

Currently, if the .eh_frame sections of the input files only contain
terminators, ld.lld emits a zero=sized .eh_frame section
which clearly doesn't meet that requirement.

The diff makes sure a terminator gets added to each .eh_frame section
and adjusts all the relevant tests to account for that.  An additional
test isn't needed as these adjustments mean that the existence of the
terminator is tested for by several tests already.

Differential Revision: https://reviews.llvm.org/D30335

llvm-svn: 296378
2017-02-27 20:44:59 +00:00
George Rimar 11992c86d9 [ELF] - Add support for access to most of synthetic sections from linkerscript.
This is important for cases like:

  .sdata        : {
    *(.got.plt .got)
...
  }

That was not supported before as there was no way to get access to 
synthetic sections from script.

More details on review page.

Differential revision: https://reviews.llvm.org/D27040

llvm-svn: 287913
2016-11-25 08:05:41 +00:00
Rui Ueyama f86cb90a2d Do not propagate section name and attributes to .eh_frame.
.eh_frame is always ".eh_frame" and its attribute is fixed.
No need to copy from inputs to outputs. GNU gold also sets
SHT_PROGBITS.

llvm-svn: 270443
2016-05-23 15:12:41 +00:00
George Rimar e72bebaf2d [ELF] - Fixed padding for CIE/FDE entries of .eh_frame section
Spec says both CIE/FDE has "Padding
Extra bytes to align the CIE structure to an addressing unit size boundary."
https://refspecs.linuxfoundation.org/LSB_3.0.0/LSB-PDA/LSB-PDA/ehframechpt.html

Patch aligns CIE/FDE entries to the size of platform pointer.

Differential revision: http://reviews.llvm.org/D15637

llvm-svn: 256141
2015-12-21 09:38:59 +00:00
Rui Ueyama 7b19c34550 Revert "ELF: Make .note.GNU-stack more compatible with traditional linkers."
This reverts commit r253797 because it was based on a misunderstanding
that lld wouldn't work on NetBSD without this change.

llvm-svn: 254003
2015-11-24 18:48:16 +00:00
George Rimar e3336c0be6 Reapply fixed r253967.
llvm-svn: 253971
2015-11-24 10:15:50 +00:00
George Rimar 11721ce810 Revert r253967 which broke buildbot.
llvm-svn: 253970
2015-11-24 10:04:22 +00:00
George Rimar 63a6ca9150 [ELF] Implements -z relro: create an ELF "PT_GNU_RELRO" segment header in the object.
Partial (-z relro) and full (-z relro, -z now) relro cases are implemented.

Partial relro:
The ELF sections are reordered so that the ELF internal data sections (.got, .dtors, etc.) precede the program's data sections (.data and .bss).
.got is readonly, .got.plt is still writeable.

Full relro:
Supports all the features of partial RELRO, .got.plt is also readonly.

Differential revision: http://reviews.llvm.org/D14218

llvm-svn: 253967
2015-11-24 09:44:28 +00:00
Rui Ueyama e79b09a616 ELF: Make .note.GNU-stack more compatible with traditional linkers.
With this patch, lld creates PT_GNU_STACK segments only when all input
files have .note.GNU-stack sections. This is in line with other linkers
with a minor difference (we don't care about .note.GNU-stack rwx bits as
you can always remove .note.GNU-stack sections instead of setting x bit.)

At least, NetBSD loader does not understand PT_GNU_STACK segments and
reject any executables that have the section. This patch makes lld
compatible with such operating systems.

llvm-svn: 253797
2015-11-21 22:19:32 +00:00
Rafael Espindola 9c8904fb38 Rename ld.lld2 to ld.lld since it is the default.
llvm-svn: 253437
2015-11-18 06:11:01 +00:00
Rafael Espindola 4b1285c55a Rename test/elf2 to test/ELF.
llvm-svn: 253313
2015-11-17 05:36:42 +00:00